Python: Where does import come from? - python-2.7

Question

I have had this strange problem with import in python 2.7
I have my app in a directory that has some subdirectoriers and more python apps running simultaneously using Pyro Name Server for communicating with each other.
When I run one of my apps, it crashes on import when calling one of sub methods.
Here is the exception:
Traceback (most recent call last):
File "ps_logic.py", line 15840, in <module>
ps_logic = PSLogic(pyro_objects, cfg_handler, status_distributor, voip_processing)
File "ps_logic.py", line 590, in __init__
self.smarthopper_initial_check()
File "ps_logic.py", line 12824, in smarthopper_initial_check
counters_compared = self.smarthopper_maintenance_action()
File "ps_logic.py", line 12928, in smarthopper_maintenance_action
status = self.smart_hopper_logic.status_get()
File "/home/app_core/flexcore/003-480/ps_logic/smart_devices_logic.py", line 203, in status_get
return SmartStatusAugmented(self.smart_obj.queue_status_get(), self.smart_obj)
File "/usr/lib/python2.7/site-packages/Pyro/core.py", line 381, in __call__
return self.__send(self.__name, args, kwargs)
File "/usr/lib/python2.7/site-packages/Pyro/core.py", line 456, in _invokePYRO
return self.adapter.remoteInvocation(name, Pyro.constants.RIF_VarargsAndKeywords, vargs, kargs)
File "/usr/lib/python2.7/site-packages/Pyro/protocol.py", line 497, in remoteInvocation
return self._remoteInvocation(method, flags, *args)
File "/usr/lib/python2.7/site-packages/Pyro/protocol.py", line 536, in _remoteInvocation
answer = pickle.loads(answer)
ImportError: No module named drivers.smart.smart_common_const
it clearly says that it cannot import drivers.smart.smart_common_const BUT the problem is, I do not have that line in my code.
If I try to find in which file that line is (cuz I have already fixed it in some), it finds me nothing:
app_core#003-481 ~/flexcore/003-480 $ grep -R "from drivers.smart.smart_common_const import" .
./drivers/.svn/pristine/23/23e13acbf9e604f179d4625e18b2b992116a98a1.svn-base:from drivers.smart.smart_common_const import *
./drivers/.svn/pristine/65/65655973d3c70a16cc982db59db8f2989366524b.svn-base:from drivers.smart.smart_common_const import *
./drivers/.svn/pristine/3b/3ba2e2518e64db9188b63247b763926544bddd90.svn-base:from drivers.smart.smart_common_const import *
app_core#003-481 ~/flexcore/003-480 $
but svn files.
I have been running my python app with -v option to find out where it is trying to import from that file. BUT it is not returning nay debug line before that exception, so I guess its something imported previously or showing nothing if import fails.
I have also deleted all *.pyc files and rebooted machine to be sure there is noting left in memory, but problem persisted.
Is there any other option how to find out where is the problem? I am starting to be desperate..

Answer 1

That PS_Logic (whatever it may be) seems to be using Pyro to do remote calls to a server. In particular the line with the following, seems to be a remote call:
self.smart_obj.queue_status_get()
The server sends back a custom object and because it uses pickle as serialization format , your client program tries to reconstruct that object. Apparently you don't have the correct modules available in your client code, because it is pickle that fails when it tries to import the required module for you (to reassemble the response into objects)
There's got to be something in the manual of that ps_logic module that tells you about how to use it correctly, and that you should have it installed in the client as well perhaps.
(It is advised to not use pickle by the way, and stick to Pyro's default serializer, but that's another story)